A type of medium for recording data by optical means. In contrast to recording data in "two dimensions" on flat disk such as DVDs and Blu-ray discs, recording data on holographic memory involves storing data in "three dimensions" throughout the whole volume of the medium. By recording data on holographic memory at higher recording density than possible with conventional optical media, it is possible to store greater volumes of data on the same type of disk as a DVD.
Moreover, although data is written to and read from conventional optical media in units of bits, it is written to and read from holographic memory in terms of two-dimensional images. As a result, it becomes possible to write and read data at higher speed.
